Pilot burner



April 18, 1961 A. H. SEARS PILOT BURNER Filed Nov. 28, 1958 YINVENTOR.QRTHUR H SEARS PILOT BURNER Arthur H. Sears, Chicago, 11]., assignor toHarper-Wyman Company, Chicago, 111., a corporation of Illinois FiledNov. 28, 1958, Ser. No. 777,077 g e 2 Claims. (Cl. 158-115) The presentinvention relates to a pilot burner and has Patented Apr. 18, 1961.

of the main burner ports 20 are located above'the charging port 14structure which communicates with the burner chamber 17 to which gas maybe supplied under the control of a conventional valve, not shown. Thecharging port structure includes a small radially outwardly directedport 22 above which is located an upwardly opening slot 24 communicatingwith the port 22 and the for its primary purpose the provision of a newand improved pilot burner of the type commonly called a tiny pilotutilized to ignite gas supplied from the charging or lighter jet of anassociated main burner.

A primary object of the invention is to provide the pilot burner withshielding to prevent overheating and; clogging of the tiny pilot, toprotect it against extinction by gas discharged from the main burnerwhich is to be lighted by the pilot burner or by extraneous air currentsor boilovers or the like which mightotherwise fall upon it, and to makeit easy to align the pilot burner relative to the main burner. r

A further object of the present invention isto provide a pilot ofthe'character aforesaid including a perforated baffle, such as a wiremesh screen, located between it and an associated main burner to belighted and which screen acts as a barrier preventing extinction of thepilot burner flame by 'gas supplied from the associated main burner andwhich will, at the same time, permit the pilot burner effectively toignite the gas whereby the main larger hollow portion 25. When'gas issupplied to the main burner, some of the gas is projected radiallyoutwardly from the port 22 to the pilot burner and some of the gas flowsupwardly through slot 24 toward the ports 20 so that the gas iszignitedby the pilot burner and it in turn ignites the gas flowing from the mainburner ports 20.

The pilot burner 10. of the present invention includes a small tube orneedle 30 having a small opening for the discharge'of gas and which iscommonly called a tiny pilot or micro pilotf' It is supplied with gas atall times to maintain a continuous pilot flame, thegas being suppliedthrough a tube 32, a coupling nut 34 detachably coupling the .tube32 toa hollow externallyihreaded fitting 36 havingits upperend closed by anintegral plate-like portion38 to whichis suitablysecured, as by peening,an aperturedshield supporting or mountingplate 40 and to which the pilotburner tube or needle 30 is also secured.

In order to prevent the minute opening of the tiny pilot 30- frombecoming clogged or overheated as well as to prevent the pilot flamefrom being extinguished by a blast of gas fromthe main burner or byextraneous air currents or the like, the pilot is shielded by twodifferent means. These means include, first, a perforated baffle suchasa wire mesh screen 42 disposed between the needle 30.and the chargingport and, second, an overlying burner will be lighted. This screen alsoserves to maintain the pilot burner cooler and spreads gas supplied toit from the main burner sothat accurate location of the pilot burner isnot required.

A further object of the present invention is to provide a pilot burneras described in the preceding paragraph with an overlying shield adaptedto carry away products of combustion from the pilot whereby theseproducts will not be likely to clog the charging port of the main burnerfrom which gas is supplied to the pilot for lighting of the main burner.

Other objects and advantages of the invention will become apparent fromthe ensuing description of an illustrative embodiment of the invention,in the course of which reference is had to the accompanying drawings,

in which: 1

Fig. 1 is a fragmentary view illustrating the pilot burner of thepresent invention in combinationwwith a main burner, the latter beingillustrated partially and in section o y; 7 r t Fig. 2 is an enlargedfront elevational view of the pilot burner of the present invention, theview being taken along the line 2-2 of Fig. 1; and

Fig. 3 is a vertical sectional view taken along the line 33 of Fig. 2. I

Referring now to the drawing and first to Fig. 1, the pilot burner ofthe present invention is indicated as a .whole by thereference'character 10. It is shown in the shield in the form of ahousing indicated as a whole by the reference character. 44; V,

The screen 42i-is located a short distance in. front of the needle 30andrises a short distance above it but does not apart side walls 52 and54. These are provided with horizontalfianges 56 at their front lowerends whereby the shield canbe secured to the mounting plate 40 bycrimping the edge portions 58 of the latter over the flanges as bestillustrated in Fig. 2. The screen 42 is secured to the plate 40 bycrimping the forward portion 60 of the mounting plate 40 over a flangedfoot portion 62 of the screen. a

The screen 42 extends substantially across the width of the shield 44 asshown in Fig. 2 and it is to be noted also that the screen, as shown inFig; 3, is inclined at an angle of about 15 upwardly and toward the tube30. Also it should be noted that the screen does not extend so as to bevertically above the tube 30 and there is substantial spacing betweenthe screen and tube to permit difiusion of the gas blast before itreaches the tube.

The screen is inclined at an angle between about 11 to 18, butit'hassbeen found that best results are obtainable if the screen isinclined at'about a 15 angle, as illustrated. The described constructionhas been found to operate satisfactorily for ignition of the gasdischarged from the charging port 22 and, at the same time, pref ventsthe pilotflame from being extinguished by the sudpilottube 30 cool, sothat gas burned thereat is prevented port or lighter jet structureindicatedv as a whole by the reference character'l l. f e v Themainburner includes a burner base'16, a burner chamber 17, and anoverlyingburner cap .18 having an annular series of main burner ports 20discharging genfrom being cracked and forming'gummy residues which It isimportant that there be a space would clog. it.

' such as the space 48 above the screen and that the screen f alsothatthe screen be inclined at an angle such as the 15 erally radiallyoutwardly and somewhat upwardly; Some} extend a short distance above thetop of the'tube 30 and angle an angle of inclination less than about 11"enemas is used,"the "gas has a tendency to burn at the pilot burnerside of the screen and the flame does not readily pass over the screento ignite the gas at the outside of the screen, i.e., to ignite the gasat the charging port 22, 24. Also, if the screen extends too far abovethe pilot tube, for example .to the top 46 of the shield, the flame willburn only at the inside of the screen and not be. passed over it. Theflame should have only its tip above the screen. It is preferable alsothat the pilot burner flame not impinge on the screen 42.. If desired, asomewhat greater angle of inclination than 15 could be used and thepilot tube 30 could be spaced a greater distance from it to avoidimpingement of the flame upon the screen.

In order to conduct the products of combustion from the pilot burnerflame away from the charging port area or region, the shield is providedwith the side walls 52 and the top 46 is inclined somewhat upwardly andaway from the charging port to provide a chimney or flue effect. Toenhance this eflect, the top and side walls are extended rearwardly awayfrom the pilot tube 30.

In operation, the pilot burner will be continuously supplied with adesired quantity of gas through the tube 32. This gas is dischargedthrough the'tiny pilot needle 30 to provide a continuous pilot flame tothe right of the -screen 42 so that at least the tip of the flameextends above the top of the screen. When gas is supplied to the mainburner chamber 17, some of the gas is projected toward the screenthrough the port 22 and some is directed above the charging portstructure 14 toward main burner ports 20 so that when this flow isignited the gas issuing from the main burnerports is also ignited.

The screen 42 prevents the gas discharge from the port 22 from blowingout the pilot burner flame. Some of the gas flows over the top of thescreen but this does not blow out the pilot burner flame. The. gas thussupplied to the pilot burner from the main burner is ignited and flashesback over the screen tothe main burner. The

screen serves to diffuse the gas passing through it to the pilot flameso that accurate alignment of pilot and charging port is not requiredand so that the pilot flame will "not be blown out and, after ignition,it serves to keep the charging port flame from directly impinging uponthe pilot burner. V

The products of combustion resulting from the pilot burner flame areconducted away from the main burner by the shield 44 whichhas a flueeffect resulting from the extended side walls and "top plate with itsupward inclination.

The shield with its top plate 46 also prevents extraneous material suchas boil-overs from extinguishing the pilot flame.

The screen is made of some suitable material, prefera-,

ably stainless steel. The screen should have a mesh between 30 and and a40 mesh, i.e., 40 meshes per inch, has been found quite satisfactory.Perforated material other-than'screening can be used.

While the present invention has been'described with an illustrativeembodiment thereof, these details are not intended to be limitative ofthe invention except insofar as set forth in the accompanying claims.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

'1. A pilot burner for a main burner having a port for discharge of gasto be ignited by the pilot'burne'r including in combination, a pilotburner extending to a predetermined height, and a screen type baflledisposed on one side of the pilot burner, said b'aflie being inclinedupwardly and toward the pilot burner, and extending a short distanceabove the height of the pilot burner, a shield overlying the pilotburner and baffl'e structure, saidshield having side walls spaced fromthe pilot burner and said screen extending substantially, from one sidewall to the other, said side walls extending some distance above thescreen and from the screen some distance beyond the opposite side of thepilot burner, and a top wall interconnecting said side walls, said topwall being inclined upwardly and rearwardly from a position in front ofthe screen to a position on said opposite side of the pilot burner.

2. A pilot burner as claimed in claim 1 wherein said screen andoverlying shield are secured to a mounting plateforming a part of thepilot burner. 7

References Cited in the file of this patent UNITED STATES PATENTS1,994,860 Matson Mar. 19, 1935 4 FOREIGN PATENTS 483,780 Great BritainApr. 26, 1938 440,680 Italy n--. Oct. 16, 1948

